000142146 001__ 142146
000142146 005__ 20190316234636.0
000142146 022__ $$a0006-2960
000142146 02470 $$2PMID$$a9254621
000142146 0247_ $$2doi$$a10.1021/bi963195p
000142146 037__ $$aARTICLE
000142146 245__ $$aGuanidine hydrochloride-induced denaturation and refolding of transthyretin exhibits a marked hysteresis: equilibria with high kinetic barriers
000142146 269__ $$a1997
000142146 260__ $$bAmerican Chemical Society$$c1997
000142146 336__ $$aJournal Articles
000142146 520__ $$aFluorescence and circular dichroism spectroscopy as well as analytical ultracentrifugation and glutaraldehyde cross-linking were utilized to evaluate the tertiary and quaternary structural changes occurring on the denaturation and reconstitution pathways of transthyretin (TTR) as a function of guanidine hydrochloride (GdnHCl) concentration. These results demonstrate that the GdnHCl-mediated denaturation and reconstitution of TTR is reversible. However, the lowest GdnHCl concentration that dissociates and unfolds transthyretin does not allow the unfolded monomer to refold to tetramer at a rate that is measurable. As a result, there is a striking hysteresis observed upon comparison of the GdnHCl-mediated denaturation and reconstitution transitions. The TTR tetramer does not dissociate into unfolded monomer until the denaturant concentration exceeds 4 M GdnHCl, whereas unfolded monomeric TTR (denatured in 7 M GdnHCl) does not refold and assemble into a native tetrameric structure until the GdnHCl concentration is reduced to less than 2 M. These results imply that a significant kinetic barrier intervenes between the folded tetramer and unfolded monomer in both the denaturation and reconstitution directions at pH 7. A kinetics study of the denaturation of TTR as a function of GdnHCl concentration yields a first-order rate constant for unfolding of (9.0 +/- 7.5) x 10(-11) s-1, estimated by extrapolation of the rate constants for the tetramer to unfolded monomer transition as a function of GdnHCl to 0 M GdnHCl. This rate is very slow; as a result, wild-type TTR is predicted to be kinetically stable as a tetrameric quaternary structure once formed. These results imply that the rate of TTR dissociation and partial unfolding to the monomeric amyloidogenic intermediate under denaturing conditions may play a role in transthyretin-based amyloid diseases.
000142146 6531_ $$aProtein Folding
000142146 700__ $$aLai, Z.
000142146 700__ $$aMcCulloch, J.
000142146 700__ $$0240880$$aLashuel, H. A.$$g167337
000142146 700__ $$aKelly, J. W.
000142146 773__ $$j36$$k33$$q10230-9$$tBiochemistry
000142146 8564_ $$s361670$$uhttps://infoscience.epfl.ch/record/142146/files/bi963195p.pdf$$yn/a$$zn/a
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000142146 937__ $$aLMNN-ARTICLE-1997-002
000142146 973__ $$aOTHER$$rREVIEWED$$sPUBLISHED
000142146 980__ $$aARTICLE